Yeah, GIMP's interface is different from most Windows apps. I don't like it either.

I had to switch to Photoshop due to needing full support for PSD files, but I used Paint Shop Pro before that. So if you aren't completely against spending some money (or if none of the tools listed in the article linked by Salem suit you), I recommend it.

Irfanview is excellent as an image viewer, it loads very quickly, and it can convert images to many of the multitude of formats that it can display. However, its paint tools seem to be limited to those also available in basic paint apps, like MS Paint.

Edit: I should mention that Adobe has moved their "creative suite" apps to a "software as a service" model, so you can use "Adobe PhotoShop Creative Cloud" for $20/Month instead of spending $600 or more on a copy of PhotoShop CS6. Also if you do buy a piece of software and you don't require the latest version, you can check sites like eBay for people selling used copies.

The most recent GIMP has a single-window mode which gives you a more normal window interface with just one window and docked panels rather than a bunch of separate windows. I like it much better that way.

A friend of mine uses Snagit, from what I've seen of it, it is mostly just for doing some editing of existing images, and not particularly useful for creating new images.